scholarly journals Effects of dietary intervention on IGF-I and IGF-binding proteins, and related alterations in sex steroid metabolism: the Diet and Androgens (DIANA) Randomised Trial

2003 ◽  
Vol 57 (9) ◽  
pp. 1079-1088 ◽  
Author(s):  
R Kaaks ◽  
C Bellati ◽  
E Venturelli ◽  
S Rinaldi ◽  
G Secreto ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Dietary Intervention ◽  
Randomised Trial ◽  
Steroid Metabolism ◽  
Sex Steroid ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Igf Binding

Postprandial changes in plasma growth hormone, insulin, insulin-like growth factor (IGF)-I, and IGF-binding proteins in coho salmon fasted for varying periods

2009 ◽  
Vol 297 (2) ◽  
pp. R352-R361 ◽  
Author(s):  
Munetaka Shimizu ◽  
Kathleen A. Cooper ◽  
Walton W. Dickhoff ◽  
Brian R. Beckman
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Food Intake ◽  
Binding Proteins ◽  
Coho Salmon ◽  
Fasting Period ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Igf Binding ◽  
Single Meal

We examined postprandial changes in circulating growth hormone (GH), insulin, insulin-like growth factor (IGF)-I, and IGF-binding proteins (IGFBPs) in yearling coho salmon under different feeding regimes. Fish were initially fasted for 1 day, 1 wk, or 3 wk. Fasted fish were then fed, and blood was collected at 4-h intervals over 26 h. After the various periods of fasting, basal levels of insulin were relatively constant, whereas those of IGF-I, IGFBPs and GH changed in proportion to the duration of the fast. A single meal caused a rapid, large increase in the circulating insulin levels, but the degree of the increase was influenced by the fasting period. IGF-I showed a moderate increase 2 h after the meal but only in the regularly fed fish. Plasma levels of 41-kDa IGFBP were increased in all groups within 6 h after the single meal. The fasting period did not influence the response of 41-kDa IGFBP to the meal. IGFBP-1 and GH decreased after the meal to the same extent among groups regardless of the fasting period. The present study shows that insulin and IGF-I respond differently to long (weeks)- and short (hours)-term nutritional changes in salmon; insulin maintains its basal level but changes acutely in response to food intake, whereas IGF-I adjusts its basal levels to the long-term nutritional status and is less responsive to acute nutritional input. IGFBPs maintain their sensitivity to food intake, even after prolonged fasting, suggesting their critical role in the nutritional regulation of salmon growth.

scholarly journals GH/IGF e neoplasia: o que há de novo nesta associação

2005 ◽  
Vol 49 (5) ◽  
pp. 833-842 ◽  
Author(s):  
Angela M. Spinola e Castro ◽  
Gil Guerra-Júnior
Keyword(s):  
Growth Factors ◽  
Binding Proteins ◽  
De Novo ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Ciclo Celular ◽  
Igf Binding ◽  
Insulin Like Growth Factors

Estudos in vitro e em animais sugerem que os membros do sistema insulin-like growth factors (IGFs), incluindo IGF-I, IGF-II, receptores de IGF-I e IGF-II (IGF-IR e IGF-IIR), e as IGF-binding proteins (IGFBPs) podem ter um importante envolvimento no desenvolvimento e na progressão de neoplasias. Mais especificamente, as IGFs promovem a progressão do ciclo celular e inibem a apoptose tanto por ação direta com outros fatores de crescimento como por ação indireta interagindo com outros sistemas moleculares intracelulares envolvidos na promoção e/ou progressão do câncer. Além disso, inúmeros estudos epidemiológicos têm sugerido que concentrações elevadas das IGFs, independente das alterações nas IGFBPs, podem estar associadas a um aumento no risco de desenvolver determinadas neoplasias. Esta revisão tem como objetivo apresentar o envolvimento do sistema IGF na regulação tumoral, os principais estudos epidemiológicos realizados e o risco de desenvolvimento de neoplasia em pacientes (com ou sem história pessoal de neoplasia prévia) que receberam hormônio de crescimento (rhGH). É importante salientar que o uso clínico de rhGH, nas indicações aprovadas internacionalmente, é seguro e não existem evidências, até o momento, da associação com o desenvolvimento de neoplasias.

scholarly journals Insulin-like growth factor (IGF)-II binding to IGF-binding proteins and IGF receptors is modified by deletion of the N-terminal hexapeptide or substitution of arginine for glutamate-6 in IGF-II

1993 ◽  
Vol 293 (3) ◽  
pp. 713-719 ◽  
Author(s):  
G L Francis ◽  
S E Aplin ◽  
S J Milner ◽  
K A McNeil ◽  
F J Ballard ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Proteins ◽  
Biological Activities ◽  
Biological Properties ◽  
Hepatoma Cells ◽  
Insulin Like Growth Factor ◽  
Igf Binding Proteins ◽  
Anabolic Response ◽  
Igf I ◽  
Igf Binding

Recombinant insulin-like growth factor-II (IGF-II) and two structural analogues, des(1-6)IGF-II and [Arg6]-IGF-II, were produced to investigate the role of N-terminal residues in binding to IGF-binding proteins (IGFBPs) and hence the biological properties of the modified peptides. The growth factors were modelled on two previously characterized variants of IGF-I, des(1-3)IGF-I and [Arg3]-IGF-I, which both show substantially decreased binding to IGFBPs and were expressed as fusion proteins in Escherichia coli. The biological activities of the corresponding analogues of IGF-I and IGF-II were compared in rat L6 myoblasts and H35B hepatoma cells. In the L6-myoblast protein-synthesis assay, the IGF-II analogues, des(1-6)IGF-II and [Arg6]-IGF-II, were slightly more potent than IGF-II but about 10-fold less potent than IGF-I and 100-fold less potent than the respective IGF-I analogues, des(1-3)IGF-I and [Arg3]IGF-I. In H35 hepatoma cells the anabolic response measured was the inhibition of protein breakdown, and the potency order was insulin >>> [Arg3]-IGF-I > des(1-3)IGF-I > [Arg6]-IGF-II > des(1-6)IGF-II > IGF-I > IGF-II. Binding of the IGFs and their analogues to the type 1 IGF receptor in L6 myoblasts and to the insulin receptor in H35 hepatoma cells did not fully explain the observed anabolic potency differences. Moreover, binding of all four analogues to the IGFBPs secreted by L6 myoblasts and H35B hepatoma cells was greatly decreased compared with the parent IGF. We conclude that the observed anabolic response to each IGF was determined by their relative binding to the competing cell receptor and IGFBP binding sites present.

Circulating insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs) and tissue mRNA levels of IGFBP-2 and IGFBP-4 in the ovine fetus

1995 ◽  
Vol 145 (3) ◽  
pp. 545-557 ◽  
Author(s):  
J M Carr ◽  
J A Owens ◽  
P A Grant ◽  
P E Walton ◽  
P C Owens ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Mrna Level ◽  
Common Factor ◽  
Late Gestation ◽  
Mrna Levels ◽  
Igf Binding Proteins ◽  
Fetal Sheep ◽  
Igf I ◽  
Igf Binding ◽  
Igfbp 3

Abstract The IGF-binding proteins (IGFBPs) are a family of at least six structurally related proteins, which bind the IGFs and modulate their actions, including the regulation of preand postnatal growth. In this study we have examined the relationship between circulating and tissue mRNA levels of IGFBPs and related this to circulating IGFs in the fetal sheep over the gestational period when rapid growth and development occurs. Circulating IGFBP-2, as measured by Western ligand blot (WLB), increases between early and mid gestation, remains high, then declines throughout late gestation (P=0·0002). Circulating IGFBP-3 increases throughout gestation, as measured by WLB or RIA (P=0·04 and P=0·0001 respectively), as does circulating IGFBP-4 (P=0·004). These ontogenic changes in circulating IGFBPs-2 and -4 are paralleled by changes in liver mRNA for these proteins and, for IGFBP-2, by those in kidney IGFBP-2 mRNA also. This suggests that liver and kidney may be the primary contributors to circulating IGFBP-2 and the liver to circulating IGFBP-4. IGFBP-2 mRNA is present in the heart and lung in early gestation but barely detectable in these tissues after approximately 60 days gestation. IGFBP-4 mRNA is also present in the heart in early but not late gestation, but is abundant in the lung throughout gestation. These results demonstrate tissue specific and developmental regulation of IGFBPs-2 and -4 at the mRNA level. To assess any role the circulating IGFs may play in mediating these changes in IGFBPs, or vice versa, both plasma IGF-I and IGF-II were measured by RIA. Circulating IGF-I increases as gestation progresses (P=0·0001), while circulating IGF-II increases between early and mid gestation, remains high (P=0·01), then declines. Circulating IGF-I is positively correlated with fetal weight (r=0·66, P=0·03), circulating IGFBP-3 (r=0·54, P=0·01) and IGFBP-4 (r=0·52, P=0·01). Circulating IGF-II positively correlates with circulating IGFBP-2 (r=0·48, P=0·02) throughout gestation and at 1 day postnatally. These relationships are consistent with circulating IGF-I influencing IGFBPs-3 and -4, and similarly, IGF-II determining IGFBP-2, or vice versa. Alternatively, these correlations may reflect coordinate regulation of IGF and IGFBP by a common factor. Journal of Endocrinology (1995) 145, 545–557

IGF-II, IGF-binding proteins and IGF receptors in pancreatic β-cell lines

1997 ◽  
Vol 152 (3) ◽  
pp. 455-464 ◽  
Author(s):  
L E L Katz ◽  
A Bhala ◽  
E Camron ◽  
S E Nunn ◽  
R L Hintz ◽  
...  
Keyword(s):  
Cell Lines ◽  
Binding Proteins ◽  
Conditioned Media ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Igf Binding Proteins ◽  
Igf Receptors ◽  
Igf I ◽  
Igf Binding ◽  
Hit Cells

The IGFs are mitogenic agents which are closely linked to regulatory processes in carbohydrate metabolism. Because limited information is available on the occurrence of the IGF system in the pancreatic β-cell milieu, we evaluated the presence of IGFs, IGF receptors, and IGF-binding proteins (IGFBPs) in the β-cell lines βTC3 and HIT T-15. Serum-free conditioned media (SFCM) from βTC3 cells contained IGF-II at concentrations greater than 100 ng/ml. High (15 kDa) and low (7·5 kDa) molecular weight IGF-II were detected both by column chromatography followed by RIA and by immunoblotting. GH (10–1000 ng/ml) conditioning of βTC3 cells stimulated IGF-II secretion in a dose-dependent manner. IGF-II mRNA was detected in βTC3 cells using Northern blots, and also showed a GH-dependent relationship. IGF-II peptide was detected in SFCM from HIT cells, albeit at lower concentrations. To evaluate the presence of IGF receptors in β-cell lines, affinity cross-linking studies were performed on βTC3 cells, demonstrating type I IGF receptors which bound iodinated IGF-II with high affinity, iodinated IGF-I with lesser affinity, and had minimal appreciable binding to iodinated insulin. Type II IGF receptors were not detected. SFCM from βTC3 and HIT cells was subjected to Western ligand blotting, which disclosed the presence of two major IGFBPs of 29 kDa and 24 kDa, characteristic of IGFBP-2 and IGFBP-4. The identity of the specific IGFBPs was confirmed by immunoprecipitation and Northern blotting. Varying the glucose concentration had no significant effect on the levels of IGFBPs, nor did preconditioning with GH, IGF-I, IGF-II, insulin, or glucagon. Levels of both IGFBPs in βTC3 cell-conditioned media increased in the presence of dexamethasone at concentrations of 10−6 m or greater. In summary, we present evidence that β-cell lines comprise an environment for GH and IGF action. We speculate that IGFs, their receptors and binding proteins function as a complex interactive system which regulates β-cell growth and function. Journal of Endocrinology (1997) 152, 455–464

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